9–13 Jul 2018
Sofia, Bulgaria
Europe/Sofia timezone

Multi-threaded Output in CMS using ROOT

11 Jul 2018, 11:45
15m
Hall 3.2 (National Palace of Culture)

Hall 3.2

National Palace of Culture

presentation Track 2 – Offline computing T2 - Offline computing

Speaker

Christopher Jones (Fermi National Accelerator Lab. (US))

Description

CMS has worked aggressively to make use of multi-core architectures, routinely running 4 to 8 core production jobs in 2017. The primary impediment to efficiently scaling beyond 8 cores has been our ROOT-based output module, which has been necessarily single threaded. In this presentation we explore the changes made to the CMS framework and our ROOT output module to overcome the previous scaling limits, using two new ROOT features: the TBufferMerger asynchronous file merger, and Implicit Multi-Threading. We examine the architecture of the new parallel output module, the specific accommodations and modifications that were made to ensure compatibility with the CMS framework scheduler, and the performance characteristics of the new output module.

Primary authors

Daniel Sherman Riley (Cornell University (US)) Christopher Jones (Fermi National Accelerator Lab. (US))

Presentation materials